The present invention relates to improvments for aircraft, and more particularly, to improvements enabling the craft to start and land on short runways.
Aircrafts of this type are known per se. They have deflection flaps provided at the trailing edges of the wings, and these flaps are moved to deflect (or not to deflect) the thrust producing jets. The engines are disposed underneath the wings and the thrust producing jets as emerging from the engines are deflected so as to contribute to lift. Flaps with gaps are used here, and the deflected jets pass through the gaps from below, and the upper portion of the flap contributes likewise to the deflection. In order to obtain adequate operation, it is necessary that the jet be directed against the wing and gap from below. This requirement, however, has the disadvantage that the thrust producing engines must have a negative angle of attack which, in turn, increases the required deflection angle. Moreover, there will be some loss in effective thrust if the angle of attack is indeed a negative one. The known landing flaps do provide an increase of circulation at the wings but the resulting acceleration is effective only after the jet exits from the gap, and the jets on the underside of the wing profile provide opposing thrust.